In Niger, farmers rely largely on organic
resources such as manure and compost to address soil
fertility problems and improve crop production.
Ironically, they do not improve the fertilizer value of
these organic resources or take into account their
decomposition and nutrient release patterns before the
application. This study aimed to assess the decomposition
and nutrient release patterns of composted
manure under field conditions and its implication on
millet and cowpea grain yield. Litterbags arranged in
randomized complete block design (RCBD) with three
replications were used to assess decomposition and
nutrient release of the compost. For the effect of
composted manure and mineral fertilizer on millet and
cowpea grain yield, two types of soil amendments
were used; three levels of compost and four levels of
mineral fertilizer. A 3 9 4 factorial experiment
arranged in RCBD with three replications was used.
After 84 days of decomposition, 40.3 and 56.5 % of
compost mass losses were recorded respectively in
2013 and 2014. In 2013, 31, 74 and 97 % of N, P and
K, respectively were released at 63 days of decomposition.
Furthermore, in 2014, N, P and K release values
of 58, 60 and 99 % were obtained at 84 days of
decomposition. Combined application of 2500 kg
ha-1 compost ? 175/100 kg ha-1 NPK significantly
(P\0.001) recorded the highest millet yields of 1762
and 866 kg ha-1 while the highest cowpea yields of
360.5 and 389 kg ha-1 resulted from the application
of 2500/5000 kg ha-1 compost ? 75 kg ha-1 DAP.
These findings suggest that, compost resulting from
cattle manure plus cowpea haulm can be used by
smallholder farmers to address soil fertility decline,
improve nutrient availability and raise pearl millet and
cowpea grain yield under strip cropping system.